Typewriting machine



W. A. DOBSON TYPEWRITING MACHINE Dec. 31, 11940.

Filed June 4, 1937 2 Sheets-Sheet l N O s B O D A. w

TYPEWRITING MACHINE Filed June 4, 1937 Z'SheetS-Sheet 2 Patented Dec. 31, 1940 UNITED STATES PATENT t me William A. Dobson, Wethersfield, c6115., assignor n to Underwood Elliott Fisher Company, New

York, N. Y., a corporation of Delaware I 7 Application June 4, 1937 Serial l lo.14 6,360

17 Claims.

This invention relates to typewriters, and in particular to touch-control devices as employed therein to adapt the type-action to the touch of the typist.

The impact force of the type against the Worksheet varies in accordance with the speed of operation. For adapting the mechanism to different individual touches, a key-tensioning device "If is employed. i

It is a featureof the invention to render the touch-control accessible, particularly as incorporated in Underwood Portable machines, for the reason that the small machine is largely used in the home by difierent members of a family. A touch-control lever, at the front of the machine, is adjacent the keyboard and is readily accessible for manipulation. Further, the control lever is operable vertically so that upward and downward movements thereof readily become associated in the mind of the typist with a lifting or lightening of the tension and an increase of the tension, respectively. Manipulation of the touch-control member therefore is rendered more easy because the control is in plain sight and the necessity of searching at the sides or back of the machine for the control lever is obviated. r

A further feature of the invention is to provide a touch-control mechanism, employing a minimum number of parts, "that-can be mounted adjacent the sides of the machine-frame, taking up very little space within the machine and adapting itself to ready installation during the manufacturing process. l

A still further feature of the invention is to provide for a universal bar common to the keylevers a pair of touch-control or key-tension springs, one of which is attached to each end V of the universal bar. Each of these springs'is 40 suspended froman end of a key-tensioning lever carried on the frame of the machine. The lever rises and thereby increases the tension. The effect of the lever is varied by means of a cam, having a handle accessible at the front of the machine. r

The characteristics of the spring are suchas to render it particularly desirable for touchcontrol mechanisms. 1

The springs are helically wound, successive body of the spring is tapered. The tapering secures light initial action of the spring as the key starts down.

Other features of the invention includethe use of a control-lever mounting which permits convolutions increasing in diameter so that thesimultaneous tensioning of the touch-control springs at opposite sides ,of, the machine; and the yieldable mounting of said control lever with relation to a detent-plate whereby the said lever is firmly held in any adjusted position and yet is easily moved over said detent-plate to any desired position. Also the various degrees of tension-adjustment are indicated by a scale adjacent the control lever and prominently displayed.

The present invention also relates to mechanism shown in co-pending applications 69,537, filed March 18,1936, nowPatent No. 2,168,516, and 103,474, filed-October 1, 1936, now Patent No. 2,168,518.

It is a feature of the invention to provide corresponding, increases in the tension of'the springs for corresponding equal increases in the adjustment of the tension lever away from normal position. For example, if the lever is moved 0 say 10, 20, 30, or 40, from normal position, .it will give corresponding equal increases in resistance to key-touch; so that the spring resistance on the keys at the greatest adjustment of the lever away from normal position would be the tension for the lowest setting plus four times the .unit increase in tension adjustment.

In practice, the increase in'resistance of the key-touch is approximately of an ounce for every notch inthe rack to which the lever may 1 be set. The trouble is avoided, of having resistance too great at the first adjustment, or too light on other adjustments, especially the extreme adjustment. I l

Other features and advantages will hereinafter appear. v g I r In the accompanying drawings, 1 a v Figure 1 is a .view in perspective, of a portion of a typewriter to which the inventionis applied, parts being broken away to illustrate the are rangement of the. touch-control means and its'40 actuating lever at the front of the machine.

Figure 2 isa view in sectional side elevation showing the touch-control lever set to produce the greatest tension for the type-action.

Figure 3 is an enlarged view in side elevation of the touch-control spring apart from the typewriter.

Figure 4, is a viewin sectional side elevation showing the relation of the key-levers and associated parts with the touch-control means in cluding the universal bar, a ribbon-feeding device being also illustrated.

Figure 5 is a view in side elevation illustrating the type-action in operating position and the touch-control mechanism in initial position. 55

Figure 6 is a View in side elevation illustrating the operating position of the type-action under greatest tension provided by the touchcontrol lever.

Figure 7 is a fragmentary transverse section showing the mounting of the touch-control lever and its associated parts. 7 Referring to the drawings in detail, types H] are arranged to strike against a platen ll carried in the usual manner in a carriage (not shown). Each type is mounted on the end of a type-bar l2 fulcrumed on a rod l3 and ,connected by a link [4 to a bell-crank l5, which is pivoted on a rod l6. Swinging movement of the type against the platen is caused by depression of a key I! mounted on the forward end of a key-lever I8, which is fulcrumed about a rod l9 suitably mounted in the machineframe. A pin 2! on key-lever l8 in engagement with slot 22 of bell-crank l causes operation of the latter when the key-lever is actuated.

Extending under the key-levers l3 and transversely thereof is a universal bar 23 having at its opposite ends the rearwardly-extending arms 23 secured to rock-shaft 25, journaled in brackets 26 mounted on a channel-bar 21 which extends between the side members 28 of a main .length by any keylever. A' compression return 'spring-3'll for each key-lever I8 is supported on I 'the'bar 2T. Tension means hereinafter described are provided'to maintain the universal bar yieldablyagainst the under side of the key-levers, so that the latter are urged upwardly against a pad 33. The pad is secured to the under side offlanged edge 34 of front cover-plate 35 which extends across the machine between the opposite sides of an outer frame 35, and is fastened by screws 3T;to suitable lugs 38 on the side members 2801*? the main frame 29.

' ,For pivotally supporting some of the key-levers such as 33 on the side members 2% of main frame 25, aligned shoulder-bushings 453 may be [riveted tosaid side members 28, so that a reduced portion 41 of each bushing may be riveted in a suitable opening in the frame side member '28. Theshoulder of the bushing abuts the inner wall iof'adjacent side member, 28. A flat or fillister head pin-(l2 inserted from the inside into each bushing '61! and held therein by a set-screw 43 affords a fulcrum for eachof tensioning leverarms 44 and some of the key-levers referred to, whichrnay be spaced from the lever-arms: M by washers 46.

The lever-arms 44 are close to the sides of the machine-frameand areout of the way of other operating, parts. These arms comprise forwardlyjjand' rearwardly extending portions 4! and 48 respectively, andtabs 45 on the forward portions "4?! of said lever-arms which engage stopplates 50 J of a tension-control device operable fromthe front'of the machine adjacent the keyboard. v .7 springs ig are carried on the rearward portionsflof the'ilever-arms M and are engaged at their opposite ends to arms 24 of the universal bar. The springs 49 effect delicate initial tensioning and are adjustable toeffect the desired touch-control.

lfn Figure 3 it will be observed that the body of the spring comprises a series of gradually increasing turns, presenting a tapered formation of thespring-body. Wide adjustment may be accomplished in a relatively short spring-length without sacrificing the sensitivity of operation, so desirable in eflecting touch-control.

The tension-control device includes a curved bar or rod 56 (Figure 1) extending laterally of the machine and mounted for oscillatory and rocking motion on the trunnion-ends 52 of screwstucls 53 threaded throughthe side members 28 of main frame 29. The rod 5i has secured to its opposite ends, by welding or any suitable means, hubs or collars 5 5, 55, each of which carries a dependingstop-plate or eccentric 50, the lower edge of which is cut to provide a cam-surface to engage the tabs 45 to actuate the levererms id in varying the tension of the springs 39. The plate at the right-hand end of rod El, extended upwardly to provide a tensioncontrol lever 58, an extended portion 59 of which protrudes through an opening 61) in the front cover-plate 35 and terminates in a finger-piece El. The extended portion 59 is provided with a protruding detent 62 which engages one of a plurality of notches or pockets 63 in a detent-plate 64 riveted or otherwise attached to the inner surface of the frame side member 28. Each trunnion-end 52 of stud 53 engages in a-suitable bore Ell in the ends of the rod or bar 5!, and, at the left side of the rod, a spring 58 is positioned in the bore between-the end of trunnion-pin 52 and the bottom of said bore, so that the bar 5| is normally urged to the right to yieldably maintain the tension-control lever 58 in contact with the detent-plate 64. Manipulation of the lever 56 causes the detent 62 to snap into the various notches or *pocket's63 of detent plate 64. In this manner, the adjustment of the tension-control or touch-control lever can'be made easily and quickly to any position desired.

Inorder to control the resistance of the keyleversto touch, the touch or tension control lever 53 may be swung up or down and yieldably held in anycset position by the detent 62 and plate 64, as described; A scale 55 (Figure 7) providingthe numerals l to '5, inclusive, co-operates with the lever 58 and the pockets or notches 53 to indicate the degree of tension afforded by adjustment of said cont'rol-lever 58.

The springs A9 afford the minimum tension with the. tension-control lever 58 in position shown in Figure 1, wherein the detent 62 is engaged in the first notch 63 in the plate 64. As the tension-control lever 58 is swungas shown in Figure 6, each eccentric 58, moving in unison with the'lever. 58, engages the tab '55 to'actuate the corresponding lever 44, sothat the spring supporting end 48 thereof is'rais'ed toincrease the power of its spring 49 to the maximum desired for touch-control. I a p In addition to the conveniently accessible location of the touch-control lever 58 at the front of the machin'e adjacent the keyboard, the graduate'd scalev makesit easy. for the individual to remember what number indicates the setting of the lever to suit-his touch. Also adjustment of the tension'of the keys is facilitated when multiple-copy work is to be done and it becomes necessary to strike the keys with greater than usual typing force.

Advantage of the movements of the rock-shaft .25 istaken to operate ribbon-shaft (Figure 4) to which is secured ratchet-wheel H, actuated by ratchet-arm H which is reciprocated by a rock arm 13 secured to shaft 25, reverse movement of wheel H being prevented by pawl M.

Variations may be resorted to within the scope the; universal bar, and manually-operable means for adjustably fixing the position of said leverarms, whereby the respective springs may be further tensioned simultaneously.

2. A typewriter, comprising, in combination, key-levers, a universal bar movable by the keylevers, lever-arms, a pair of tapering helical springs connecting said universal bar and the respective lever-arms and initially tensioned to impart a minimum of resistance to motion of the universal bar, and a touch-control member disposed at the front of the typewriter adjacent the keys and operable to determine the angular position of said lever-arms to tension said springs.

3. A typewriter, comprising, in combination, key-levers, a universal bar movable by the keylevers, lever-arms, a pair of tapering helical springs connecting said universal bar and the respective lever-arms and initially tensioned to impart a minimum of resistance to motion of the universal bar, eccentrics arranged to engage the end of each lever-arm, whereby to'adjustably fix the position of said lever-arms to further tension each of said springs uniformly and simultaneously, and a touch-control lever for operating said eccentrics, whereby the resistance of said pair of springs may be adjusted at will.

4. A typewriter, comprising, in combination, key-levers, a universal bar movable by the key- Ievers, lever-arms, a pair of tapering helical springs connecting said universal bar and the respective lever-arms and initially tensioned to impart a minimum of resistance to motion of the universal bar, a bar mounted for pivotal movement, an eccentric at each end of said bar and arranged for contact with a free end of each lever-arm, whereby both of said springs are further tensioned simultaneously to increase the resistance on the key-levers, and a control lever on said bar for adjustably positioning the eccentrics. said control lever being disposed at the front of the typewriter and adjacent the keys,

5. A typewriter, comprising, in combination, key-levers, a universal bar'movable by the keylevers, lever-arms, a pair of tapering helical springs connecting said universal bar and the respective lever-arms and initially tensioned to impart a minimum of resistance to motion of the universal bar, a bar mounted for pivotal movement, an eccentric at each end of said bar and arranged for contact with a free end of each lever-arm, whereby both of said springs are furthertensioned simultaneously to increase the resistance on the key-levers, a finger-lever at the front of the typewriter for operating said bar, a detent for retaining the finge -lever at any ariiustable position, and a scale for indicating the degree of tension afforded by the adjustment of said finger-lever.

6. A typewriter, comprising, in combination, key-levers, a universal bar movable by the keylevers, lever-arms, a pair of tapering helical springs connecting said universal bar and, the respective lever-arms and initially tensioned to impart a minimum of resistance to motion of the universal bar, adjustment-means mounted for pivotal and lateral movement and arranged to vary the position of said lever-arms,whereby to further tension said springs in yieldably opposing depression of the key-levers, a touch-control lever for varying said adjustment-means, a detent for holding the lever at any varied position, and means for yieldably opposing lateral movement of the adjustment-means and movement of said control, lever relative to said detent.

'7. A typewriter, comprising, in combination, a series of key-levers, a universal bar movable by the depression of the key-levers, a pair of tapering helical springs connected respectively to each end of said universal bar and initially tensioned to impart a minimum of resistance to motion of the key-levers, an adjustable anchorage for each of said springs, adjustment-means to simultaneously vary the initial tension of said springs, comprising a bar mounted for pivotal movement and extending across the machine, actuating means carried at each end of said bar, means for varying the setting of said actuating means, and meansfor transmitting the setting of the respective actuating means to the respective springanchorages.

8. A typewriter, comprising, in combination, a series of key-levers, a universal bar movable by the depression of the key-levers, a pair of tapering helical springs connected respectively to each end of said universal bar and initially tensioned to impart a-minimum of resistance to motion of the key-levers, an adjustable anchorag for each of said springs, adjustment-means to simultaneously vary theinitial tension of said springs, comprising a bar mounted for pivotal movement and extending across the machine, actuating means operatively connected to the respective springanchorages to vary the tension of said springs, and means for selectively varying the setting of said actuating means.

9. A typewriter, comprising, in combination, a series of key-levers, a universal bar movable by the depression'of the key-levers, a pair of tapering helical springs connectedrespectively to each end of said universal bar and initially tensioned to impart a minimum of resistance to motion of the key-levers, an adjustable anchorage for each of said springs, adjustment-means to simultaneously vary the initial tension of said springs, comprising a bar mounted for pivotal movement and extending across the machine, actuating means operatively connected to the respective springanchorages to vary the tension of said springs, and means for selectively varying the setting of said actuating means, presenting a finger-lever on said bar yieldably engaging a detent-member on the machine.

10. In a typewriter, the combination with typekey levers, of a universal bar for returning the key-levers, a pair of sugar-loaf springs connected to the ends of said universal bar, adjusting means connected to said springs for simultaneous adjustment, a finger-piece connected to said adjusting means, and a rack to co-operate with said finger-piece, the increase in tension of the springs being in proportion to the distance moved by the finger-piece along the rack.

11.In a variable touch typewriter having key controlled type actions; a key touch regulating device comprising a universal bar actuatable uniformly throughout its length by any type action, a pair of key touch affecting springs directly engaging the opposite ends of the universal bar, a key touch regulator settable at will to difierent key touch defining positions, and an operating in i connection from said regulator to both of said springs, said regulator and connection being arranged to keep both springs under initial tension, and to vary the initial tension of both springs simultaneously in correspondence with the setting of said regulator to different positions.

12. In a variable touch typewriter having key controlled type actions; a key touch regulating device comprising a universal bar actuatabl-e uniformly throughout its length by any type action, a pair of key touch affecting springs directly engaging the opposite ends of the universal bar, a key touch regulator settable at will to difierent key touch defining positions, and an operating connection from said regulator to both of said springs, said regulator and connection being arranged to keep both springs under initial tension,

and to vary the initial tension of both springs simultaneously in correspondence with the setting of said regulator to different positions, said type actions including key levers operable in printing and return strokes and said universal bar being normally disposed relatively to said key levers so that said springs are effective substantially throughout the printing strokes of said key levers.

13. In avariable touch type-writer having key controlled type actions; a key touch regulating device comprising a universal bar actuatable uniformly throughout its length by any type action, a pair of key touch affecting springs directly engaging the opposite ends of the universal bar, a pair of movable anchorages for said springs, a key touch regulator settable to difierent key touch defining positions, and an operating connection from said regulator .to both of said anchorages, said anchorages, connection and regulator being arranged to keep both springs under initial tension, and to vary the initial tension of both springs simultaneously in correspondence with setting said regulator to different positions.

14. -A typewriter including a plurality of depressible key-levers, a universal bar engageable by said key-levers, a lever mounted on the typewriter, said lever being connected by a spring with said universal bar, an adjustable stop engaging and retaining the lever in various angular positions thereof, whereby said spring may be variously tensioned, and means, at the front of the machine, for adjusting the stop.

15. In a variable-touch typewriter having a series of key-levers, the combination with a universal bar actuatable by said key-levers, of a spring connected to said universal bar and initially tensioned to yieldably hold said bar in normal position, a movable member supporting said spring, and an eccentric operable at the front of the machine for setting said member to vary the tension of said spring.

16. In a typewriting machine, the combination of type actions including printing keys, spring means exerting a resistance to the actuation of said type actions, and touch regulating means for increasing or decreasing the force of said spring means thereby varying the touch on the printing keys, said touch regulating means comprising a pivoted manually set controlling member mounted at the front of the machine, indexing means to indicate the positions of adjustment of said controlling member, and a tensioning member cooperative directly with said spring means and withsaid controlling member, thelatter having a cam that coacts with an operative connection on the tensioning member that is adjustable by said (cams towards and from the pivotal center of the controlling member to vary the force of said spring means. I

17. In a typewriting machine, the combination of type actions including printing keys, a universal bar actuated thereby, a spring for returning said universal bar to normal position, and touch regulating means for varying the touch on the printing keys, comprising a pivoted manually set controlling member mounted at the front of the machine and having a cam thereon, indein'ng means for indicating different positions of adjustment of said controlling member, and a pivoted lever to which one end of said spring is anchored, said lever having a part thereof that coacts directly with said cam and is movable thereby towards and from the pivotal center of WILLIAM A. DoBsoN. 

